Filament for incandescent lamps.



PATENTED OUT. 22. 1907.

- E. MoOUAT & H. W. F.- LORENZ.

FILAMENT FOR INGANDBSGENI LAMP3. APPLICATION FILED JUNE 29, 1904.

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WITNESSES: /NV EN]'0/?6 Eugene 11 0am? Hera) iffEZarenz UNlTED STATES PATENT OFFICE. I

EUGENE McOUAT AND HENRY W. F. LORENZ, OF AMSTERDAM, NEW YORK.

FILAMENT FOR INCANDESGENT LAMPS;

Specification of Letters Patent.

Patented Oct. 22, 1907.

Application filed June 29, 1904. Serial No. 214,631.

descent lamps, and the object of our invention is to provide a new process by which said filaments be plated cheaply, rapidly and effectively.

Reference is to be had to the accompanying drawings which form part of this specification, in which drawings like characters of reference indicate like parts inthe several views, and in which Figure 1 represents a filament which is formed according to our process; Fig. 2 represents a short por- .tion of a filament formed according to our invention,

the coating thereof being represented in cross section; this view being upon a much enlarged scale; and Fig. 3 represents in section upon a much enlarged scale a I portion of the coating of the carbon core, which is fixed to the core by our process.

We attain our object by the use oLthe following process: We provide a slightly adhesive liquid or semi-liquid, which is preferably the well-known caramel mixture of water and burnt sugar. To this we add suitable quantities of finely-divided metal in any orm,'including oxids or nitrids. The mixture is then thoroughly stirred so as to bring the metallic particles into mechanical suspension in the liquid. The filaments to be plated, which are preferably composed ofcarbon, are then dipped into this mixture, which may be agitated, meanwhile, to-maintain aperfect suspension of the metal particles. When the'filaments are withdrawn they will be completely covered with a coating composed largely of metallic particles: which adhere with the sugary liquid to the body ofthe filament. The dipped filaments are then subjected to a high heat for the purpose of baking or solidifying the adhering semi-liquid coat.

The baking is preferably effected in a vacuum, -or partial vacuum, or in an indifferent gas, so as to prevent the oxygen of the air from acting upon-the ingredients composing the coating of the filaments.

In cases where metals are used in the mixture, .the

' filaments may be in the usual manner. The

baking process, chars 'the caramel, and the charred. particles are afterward converted into pure carbon when the filaments are flashed or heated to ahigher temperature. The carbon particles of the caramel solution after being carbonized unite'to the carbon filament and bind the metal particles to the carbon core, thus forming a complete homogeneous coating on the carbon core. By this process the metal particles constituting the plating are cemented together by particles of carbonaceous matter and adhere to the carbon core of the filament to form a continuous uninterrupted enveloping coat.

' A filament made according to our inventionand presenting substantially the appearance of anordinary incandescent filament, is illustrated in Fig. 1. .In Fig. 2, 1 represents the carbon core of the filament. In'the completed filament this. core is enveloped in a coating 2 of the carbonized sugar of the binder, and this coating 2 is, surrounded and enveloped in a second coating 3, which consists in the finely divided particles of metal cemented together by the carbonized sugar which is located in the interstices between the particles. The carbon coat 2 occurs by reason of the fact that the particles of metal will not adhere directly to the core 1, but will adhere to the outer side of the course, adheres tightly to the carbon core, and in this way a very compact and serviceable filament is produced. In Big. 3 the small metal particles 4 are represented as highly magnified, the same being securely cemented together by the carbonized sugar 5 deposited in the interstices therebetween.

All metals can be applied as suggested by applicants method but only such as are of a suitably high melting .coat of carbonized sugar. The carbonized sugar, of

answer the purpose well. A partial list of such metals 7 includes titanium, tungsten, molybdenum, uranium, thorium, tantalum, vanadium, columbium, chromium, manganese, cobalt and nickel.

Having thus described our; invention, we claim as new and desire to secure by Letters Patent:

The process of making incandescent filaments, which consists in dipping a carbonized core in a caramel solution containing'finely divided metallic light-emittingparticles in mechanical suspension whereby a coat is deposited on said core through which said particles are dispersed, and carbonizlng said coat to render said coat and s id parti'cles integral with said core.

Signed at Albany, N. Y. thisflfithday of June 1904,

T EUGENE McOUAT.

, HENRY W. F. LORENZ;

Witnesses:

WALTER E. 1120,, FRAN KLIN' HAVENS. 

